This video should win awards. All of your videos are amazing but this one really just opened my eyes to heat treating and then tempering. Literally an instant light bulb illuminated when you were heating that chisel and watching the colors dance across. Thank you for making these and I look forward to more.
I never knew that it was possible to do this kind of work with a cold chisel. I have been a structural engineer for 35 years and this is the most informative lesson in heat treating that I have ever seen. Thank you.
Very nice explanation. I've done lots of tempering, but your tips about doing it slowly really sunk in and will change the way I do things. Thanks, and keep up the great work!
That was brilliant, simply the best demonstration of tempering possible. I was aware of the colors and temperatures, but not the technique. Now it's perfectly clear. Many thanks!
Brilliant video for me! Much appreciation to you for the information. I especially love the audio over the tempering. It was nice to hear something I've read about several times while I could see it and it clicked.
Excellent video my guy. Just the right amount of detail for a beginner, and no more. Perfect length, and really good demonstrations of everything about the color, and how to move the heat to the working edge. I appreciate the good work dude, it really shows. Keep it up!
Actually I am just starting a new series on basic blacksmithing in order to expand on the few videos I now have. " How to set up a forge " is the first video. I'm always looking for suggestions or problem areas. Thanks - stay tuned
+DF - In The Shop that's good to know, keep up the good work! As a beginning Smith I am having a problem with my work getting cracks in it. What is a common issue that causes that? My thought is I am probably working the piece at too cool of a temp.
Assuming you are not burning the metal in the fire - Cracking is mainly due to work hardening which is basically forcing the metal beyond its elastic limits. This can happen in tool steels when you forge it below the critical temp or with wrought iron if you do any forging bellow a yellow heat. The other way to cause cracking is to simply overwork the metal. Even if you are forging at the proper temp and you are doing everything right there is still a limit that the metal can take. You see this most often when you are trying to draw a bar to a point. A novice will flatten the bar to a chisel point then turn it 90 degrees and the flatten it to a chisel point in that direction and will keep repeating that process trying to get a point. Changing the cross sections that much over an over puts a tremendous amount of stress into the bar and usually results in the point splitting.
Very informative and interesting. Thank you so very much for sharing your knowledge on this aspect of forging tools. This will definitely help me with making better "stuff " in the future. I have subscribed and look forward to more. Again, thank you so much for sharing. I really appreciate it.
Ive forged stainless lots of times. .. it's much harder I can say! just never made tools I needed with it. thanks for responding. I really enjoy your videos!
I'm trying to make a shake out a leaf spring (why buy when you can make), I know that type of steel will work fine as a general purpose tool steel, so I've been looking into a lot of videos on the tempering process, and this one is so far the simplest and most concise. Well, now that I've straightened it with a torch, its off to normalising. Thank you for the info.
Sir, I’m afraid to say, that which you are describing as “Annealing”, heating to critical temperature and allowing to cool to room temperature is actually not “Annealing” but rather “Normalizing”. With annealing the steel is cooling at a very slow rate, unless you are doing a sub-critical spheroidizing anneal.
Great description on the tempering process, however I would like to know more about the process of bringing the metal up to temperature before you do your quench for hardening. Most blacksmiths talk about bringing the metal to non magnetic prior to the hardening quench.
Very nice video, that's exactly what I was looking for :-) Would be just perfect if you could add as a reminder, in the video comment, the temperatures (in F, and Celsius if possible) of each number, and maybe the use of each temperature (for wich type of tools or tool part). Tks anyway.
so nice not to see you dont have to wory about the end edge like with stone or end grain on wood.....sonework chisels are tempered the exact same way.. firesharp. and sometimes quencheing the tip in oil but leaving the middle red hot ....so the heat can bleed down to the tip slowly.
I wish I could wrap my head around this a bit better I gues hands on is my next step, Im making a forge from either a coffee can or from a special kind of brick either will be using a standard handheld propane torch.. wish me luck!
Hey i started to learn forging and i would like to try to make some basic tools like a chisel and stuff like that. My question is what type of oil are you using and whats the best or worst oil to use. It would help me a lot ^^
The worst oil is recycled motor oil which is what I happen to be using in the video. Since then I have switched to canola oil. It works great on spring steel and it doesn't put out toxic fumes when you quench your steel. It just smells like french fries. If you are purchasing tool steel, the spec sheet will recommend what oil to use.
Thanks for explaining so well the tempering process. I am a bit puzzled by you annealing the piece before quenching, however. I thought annealing, contrary to normalizing, would increase the grain of the steel to a very large size. And if this is not fixed during during the quenching, one ends up with a piece with large grains (which i read is not as tough and hard as metal with small grain). Can you explain in more details that part of the process please and your motivations? Thank you for a great video! :)
Annealing and normalizing are basically the same process - heating to above critical to refine grain structure and remove stress. The only difference is in annealing the cooling rate is slowed down a allow the steel to be as soft as possible for machining or other cold metalworking processes. So heating the metal to critical does not enlarge the grain. It is what you do to repair metal that has been overheated and quenched. I am actually normalizing here because I am letting the bar air cool instead of putting it in ashes to allow it to cool slowly to anneal. I am not a metallurgist but using the wrong terms can be confusing to people that wan't to get it right. . Just to be clear- all i am trying to do here is refine the grain structure and remove any stress in the bar that might be left over from the forging process. If I was using an extremely hard steel and i needed to drill into it, I would cool the metal very slowly ( anneal ) but I just need the bar to be stress free so I am letting the bar cool in air ( normalize ) but I would call both processes annealing out of force of habit. I will try to work on that. Thanks
Thanks so much Denis. :) Now I follow you. I am no metallurgist either, hence my question. Little tangent: I found a very nice book intended for blacksmiths that gives the basics of metallurgy: "Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel " by John D. Verhoeven. It is fairly recent, intended for the average blacksmith and it is FREE for download (as specified in the preface). Here is a download link: www.hybridburners.com/documents/verhoeven.pdf. I find it a great read and really connects the theory with practice and what comes out of the shop at the end of the day. Keep the great videos coming! Can't wait to see that box finished! :)
You can toughen those metals and make them a little more spring like by hammering the surface to work harden it but you can't heat treat them to get the results that you do with steel.
Yes it was. The strength of the cutting edge is largely determined by the accuracy of the bevel. If you get that right you can get pretty good results with lower carbon steels.
The friction from the grinder is heating up the end of the tool and drawing the temper making the edge too soft for most tools. The steel hasn't beed damaged but you either need to grind past the blue colour ( without burning the edge again ) to reach new steel that is the correct temper or redo the entire hardening and tempering process to renew the edge.
You need to quench tools when you are drawing the temper with a heat source like a torch because one end of the tool is being overheated to force the temper colors to travel to the other end of the tool. Quenching freezes the temper colors where you want them as well as cools any remaining heat that is built up in the tool. If you didn't cool the entire tool the heat built up in the handle end of the tool would continue to travel down and ruin the temper. You don't need to worry about this if you are using an oven or furnace that is set for the exact temp you need because there is no chance of overheating the tool.
The bucket in the video was full of used hydraulic oil. Over the years I've topped it up a few time with used motor oil. So now I would guess it's 50/50? I haven't noticed any difference in performance.
If you mean the black fire scale - you need to heat the steel until it reaches at least a bright red colour. At that temperature or above the steel will react with the air to form the scale. Once you have cleaned off the surface to draw the temper for a tool you cannot reheat the steel to that high temperature and replace the scale without ruining the temper.
The oil i use is mostly used motor oil. Oil hardening steels are designed to be hardened in oil. They need a slower reaction time so if you use water the amount of stress developed in the quench will cause a lot of warping and cracking.
Are these steps correct? 1) check critical temperature - when it stops being magnetic 2) heat to critical temperature, quench in oil 3) if not glassy hard, retry and quench in water. if not glassy hard, stop trying 4) heat it to critical temp and let it cool off naturally - it's now soft 5) grind it or heat it until red, shape it by hammering - stop hammering when it gets to critical temperature, repeat 6) heat it to whatever oxidation color is needed for that type of tool, quench it in oil.
So, the tempering is done after the hardening in order to release post tension in the steel? But as long as the edge doesn't get blued, it will keep its hardness?
The annealing process (before hardening ) is designed to reduce the stress in the metal to prevent cracking or warping. Tempering removes some of the brittleness from the hardening process. Most tools need a little bit of flex to hold up well. The temper colors are used to show how much the steel is being heated. At a blue temper color you will have removed to much of the hardness for most types of cutting tools. Tempering balances the amount of hardness you need with the amount of shock resistance or flex you need. Files for example are not tempered because they need to be glass hard while springs are tempered to a full blue because they need to be very flexible.
Files should not be left at a full hard condition. Glass hard also means the metal will shatter just as if it was made of glass, not something you want in any cutting tool including files. Several years ago I tested some small spring steel after the quench. It shattered and flew everywhere.
@@khayyam741 Just we are clear, failure to do any tempering on a steel cutting tool will make it extremely hard and therefore very efficient at cutting. As long as it doesn't chip or break. A file is just a lot of little chisel teeth formed on a steel blank. And you really want it to survive being used. So a slight amount of temper will bring it off that glass hard state.
Hi, are there more different techniques of tempering or what, I thought that you temper it by heating it to desired temp. as described but than letting it cool slowly on room temperature?? I m confused
but i m confused because I see some guys temper it by leaving it cool at room temp. and some heat it to tempering temp. and then quench it ( for the second time )
Sometimes you need to quench the part of the piece you are tempering with a torch to stop the temper colors from advancing if you have an excess amount of heat built up in the tool. Quenching doesn't affect the quality of the tempering - it's just a way of regulating the temperature. Just make sure that you don't quench any part of the tool that might be at a red heat because it will become brittle. Tempering in an oven does work great and it's the best way to make sure that you get the exact temper you want. Start at 400 & raise the heat slightly every 1/2 hour or so until you get the colors you need. The first time you do it take note of all the colors you get at the different temps so you can start closer to that mark next time.
If you are talking about taking it to the critical temp and then letting it cool slowly that is a totally different part of the process. It is confusing because some people also call that tempering but it is really called normalizing. That process is to reduce the stress in the metal before hardening. That stress will cause knife blades to warp or crack. After forging or shaping you normalize, then you harden and then you temper. When you hear people say their blades are triple tempered they are actually normalizing the blade 3 times to ensure all stress is removed before hardening.
Thanks for the answer, I dont think on normalizing, I know that s a different process with a different purpose like you said, but I thought tempering is done after hardening by heating the metal piece to wanted temperature ( light straw to blue depending what properties you need ) and than just let it cool slowly in owen, room temp. ....., did t think you can temper it just by getting to wanted tempering temperature an cooling it quickly by quenching. Wikipedia also says this ( but found and heard that in more places than wiki :) ): "Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air." Or there are simply two possible options for tempering: 1. get to tempering temperature and just let cool 2. get to tempering temperature and quench????
The stainless knife makers use ( or once did ) is 440c. I've never worked with it so I can't comment on how it forges but I do remember in the 80's that it was a pretty big deal that some guys were able to forge stainless so I imagine it has it's problems. Better check with the bladesmiths before you put too much time into something.
There are so many varieties of stainless, some suitable for knives, some not. 440C, which is common for knives (and pretty much all stainless in general) is very difficult to forge. Most knife makers who do stainless typically make them in what is known as the "stock removal" method. In other words, they buy their stainless in pre-cut lengths, widths and thicknesses, then use their grinders to shape the blade, bevels, etc, then send it out to a commercial heat treater. Stainless requires precise and complex heat treating in multiple cycles. You do not harden and temper stainless by heating it and quenching it in the same manner as carbon steels. It requires lengthy periods of time at precise temperatures and also precise cooling rates and multiple heating and cooling cycles. Stainless has a very small heat range where it can be forged with a hammer. Too low and it just won't move, go slightly over the ideal range and it will crumble like cottage cheese. Even at the ideal temperature, it takes twice as much, if not more, force to forge it. If you try to work at a temp lower than ideal then you hazard shattering or cracking it. Many knife makers never try to forge it at all and just use the stock removal method of they want to make a stainless knife.
This video should win awards. All of your videos are amazing but this one really just opened my eyes to heat treating and then tempering. Literally an instant light bulb illuminated when you were heating that chisel and watching the colors dance across. Thank you for making these and I look forward to more.
I never knew that it was possible to do this kind of work with a cold chisel. I have been a structural engineer for 35 years and this is the most informative lesson in heat treating that I have ever seen. Thank you.
I'm a metallurgist and this was a great video.
I don't think I've ever seen tempering explained this well. Thank you.
I just found these videos of yours and needed them horribly! It is a gold mine of info and experience. Thanks so much!
Dave Sam same I made a springy titanium knife with this info
One of my favorite channels on blacksmithing . This guy has a vpice that makes me feel calm , confortable , Congratulations !
Your beginner videos are the best I have been able to find. Thank you, sir.
same here
You're a patient and detailed instructor and I appreciate your time , thanks
Greatest forging videos EVER! Thanks so much for being clear, concise and informative while also not being dull
Thank you this is the best demonstration I have seen after watching many. Thank you so much
after annealing my first set of tools and getting super confused, this video really opened my eyes to what was really happening. Thank you!
Very nice explanation. I've done lots of tempering, but your tips about doing it slowly really sunk in and will change the way I do things. Thanks, and keep up the great work!
Best 4mins &:44 seconds on You Tube. Thank again Sir
That was brilliant, simply the best demonstration of tempering possible. I was aware of the colors and temperatures, but not the technique. Now it's perfectly clear. Many thanks!
Brilliant video for me! Much appreciation to you for the information. I especially love the audio over the tempering. It was nice to hear something I've read about several times while I could see it and it clicked.
I find visuals are always better than text.
Best color tempering video I have seen. Very informative! Thanks!
This is good stuff Dennis. Fair play to you.
This should have waaay more views. Thank you!
Excellent video. You always read about running the colors. But it makes a lot more sense when you see it. I can hardly wait to get my forge built.
Excellent video my guy. Just the right amount of detail for a beginner, and no more. Perfect length, and really good demonstrations of everything about the color, and how to move the heat to the working edge. I appreciate the good work dude, it really shows. Keep it up!
possibly the nicest chip I've ever seen...
Thank you Denis for all the great information! These are some of the best videos on "how to" I have seen on UA-cam for beginning smiths.
Actually I am just starting a new series on basic blacksmithing in order to expand on the few videos I now have. " How to set up a forge " is the first video. I'm always looking for suggestions or problem areas. Thanks - stay tuned
+DF - In The Shop that's good to know, keep up the good work! As a beginning Smith I am having a problem with my work getting cracks in it. What is a common issue that causes that? My thought is I am probably working the piece at too cool of a temp.
Assuming you are not burning the metal in the fire - Cracking is mainly due to work hardening which is basically forcing the metal beyond its elastic limits. This can happen in tool steels when you forge it below the critical temp or with wrought iron if you do any forging bellow a yellow heat. The other way to cause cracking is to simply overwork the metal. Even if you are forging at the proper temp and you are doing everything right there is still a limit that the metal can take. You see this most often when you are trying to draw a bar to a point. A novice will flatten the bar to a chisel point then turn it 90 degrees and the flatten it to a chisel point in that direction and will keep repeating that process trying to get a point. Changing the cross sections that much over an over puts a tremendous amount of stress into the bar and usually results in the point splitting.
Great video. Very logical explanation of The tempering process. Thank you.
:O chiseling that piece of steel blew my mind.
Really well presented. VERY helpful. Much appreciated and thanks!
Thanks for very informative videos.
thank you for passing on the knowledge.. much appreciated👍
The chisel came out amazing.
Great videos, thank you for sharing your knowledge!!!!
wow you can actually see the spectrum travel down the chisel , so cool
There is a hell lot of info in the comments section of this video. Thanks to admin and others for replying all of the comments.
This was exact information i was looking for thank you wonderful video
Excellent tutorial
Very informative and interesting. Thank you so very much for sharing your knowledge on this aspect of forging tools. This will definitely help me with making better "stuff " in the future. I have subscribed and look forward to more. Again, thank you so much for sharing. I really appreciate it.
Ive forged stainless lots of times. .. it's much harder I can say! just never made tools I needed with it. thanks for responding. I really enjoy your videos!
Another excellent lesson. Thank you.
thankyou very much. you explain things very well.
This is exactly how an instructional video should be. :)
Thankyou I have been wanting to understand this for a while. Your video was very easy to understand.
....soooo intersting !!! Thank You sooo much !! kinde rgards from Switeland !!
highly instructive
Beautiful temper work there. :)
I agree . Thank you sir... A little info from a master goes a very long way.
I am steel learning. Lol
Excellent tutorial :D
I'm trying to make a shake out a leaf spring (why buy when you can make), I know that type of steel will work fine as a general purpose tool steel, so I've been looking into a lot of videos on the tempering process, and this one is so far the simplest and most concise.
Well, now that I've straightened it with a torch, its off to normalising.
Thank you for the info.
Very interesting and Good 👍
Great info. Thanks!
that was a good one, a very good one :-) thank you
THANK YOU. my mind is blown.
Awesome video!!!!!!
WOAH!!! Amazing!
I liked the way you made me understand like nothing good lesson thanks. I'll look for more videos.
Annealing is softening hardened steel. Normalizing is realignment of structure before heat treat.
🔪 As far as I'm concerned, The DF stands for "Damn Fine"!!
Amazing!
❤️❤️👍good all the best
Sir, I’m afraid to say, that which you are describing as “Annealing”, heating to critical temperature and allowing to cool to room temperature is actually not “Annealing” but rather “Normalizing”. With annealing the steel is cooling at a very slow rate, unless you are doing a sub-critical spheroidizing anneal.
old school skill rite there
Great description on the tempering process, however I would like to know more about the process of bringing the metal up to temperature before you do your quench for hardening. Most blacksmiths talk about bringing the metal to non magnetic prior to the hardening quench.
That is covered in part 1& 2 of this series.
Thank You !
thanks U brother
Excellent video mate,. may I assume when you say your temperatures you are speaking in Fahrenheit?
Very nice video, that's exactly what I was looking for :-)
Would be just perfect if you could add as a reminder, in the video comment, the temperatures (in F, and Celsius if possible) of each number, and maybe the use of each temperature (for wich type of tools or tool part).
Tks anyway.
Could you please put the temperatures beside the numbered oxidized plates, this would be extremely useful.
excellent!!
Clair et précis, les commentaires sont presque superflus , parfait !!!
so nice not to see you dont have to wory about the end edge like with stone or end grain on wood.....sonework chisels are tempered the exact same way.. firesharp. and sometimes quencheing the tip in oil but leaving the middle red hot ....so the heat can bleed down to the tip slowly.
can it be more specific like no.1 colour/ hardness is for chisel, knife or axe etc..??
I wish I could wrap my head around this a bit better I gues hands on is my next step, Im making a forge from either a coffee can or from a special kind of brick either will be using a standard handheld propane torch.. wish me luck!
at 1:15 is the cars/ motorbikes' engine oil?
Hey i started to learn forging and i would like to try to make some basic tools like a chisel and stuff like that. My question is what type of oil are you using and whats the best or worst oil to use. It would help me a lot ^^
The worst oil is recycled motor oil which is what I happen to be using in the video. Since then I have switched to canola oil. It works great on spring steel and it doesn't put out toxic fumes when you quench your steel. It just smells like french fries. If you are purchasing tool steel, the spec sheet will recommend what oil to use.
What is the ideal heat level for a blade?
so where did you get the springs? did you remember?
Badass
What is the article and thank you
Thanks for explaining so well the tempering process. I am a bit puzzled by you annealing the piece before quenching, however. I thought annealing, contrary to normalizing, would increase the grain of the steel to a very large size. And if this is not fixed during during the quenching, one ends up with a piece with large grains (which i read is not as tough and hard as metal with small grain). Can you explain in more details that part of the process please and your motivations? Thank you for a great video! :)
Annealing and normalizing are basically the same process - heating to above critical to refine grain structure and remove stress. The only difference is in annealing the cooling rate is slowed down a allow the steel to be as soft as possible for machining or other cold metalworking processes. So heating the metal to critical does not enlarge the grain. It is what you do to repair metal that has been overheated and quenched. I am actually normalizing here because I am letting the bar air cool instead of putting it in ashes to allow it to cool slowly to anneal. I am not a metallurgist but using the wrong terms can be confusing to people that wan't to get it right. . Just to be clear- all i am trying to do here is refine the grain structure and remove any stress in the bar that might be left over from the forging process. If I was using an extremely hard steel and i needed to drill into it, I would cool the metal very slowly ( anneal ) but I just need the bar to be stress free so I am letting the bar cool in air ( normalize ) but I would call both processes annealing out of force of habit. I will try to work on that. Thanks
Thanks so much Denis. :) Now I follow you. I am no metallurgist either, hence my question. Little tangent: I found a very nice book intended for blacksmiths that gives the basics of metallurgy: "Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel " by John D. Verhoeven. It is fairly recent, intended for the average blacksmith and it is FREE for download (as specified in the preface). Here is a download link: www.hybridburners.com/documents/verhoeven.pdf. I find it a great read and really connects the theory with practice and what comes out of the shop at the end of the day. Keep the great videos coming! Can't wait to see that box finished! :)
@@df-intheshop330 👍
0:30 does it need to cool in the shade
Can you make a spring out of any material like: copper, gold, aluminum ect?
You can toughen those metals and make them a little more spring like by hammering the surface to work harden it but you can't heat treat them to get the results that you do with steel.
👍👍👍
Wow! Was that chisel still sharp after cutting the bevel 2" long?
Yes it was. The strength of the cutting edge is largely determined by the accuracy of the bevel. If you get that right you can get pretty good results with lower carbon steels.
bonjour
vos vidéos sont superbe j’en suis passionne .pouvez vous svp essayer de mettre des sous titré en français .si cela est possible merci monsieur
could I use this technique on steel square rods that have been angle grinned?
Yes the process would be the same regardless of the shape of the steel you are using.
If you overheat a chisel with a grinder and it goes blue, what has actually happened to the steel?
thanks for the video
The friction from the grinder is heating up the end of the tool and drawing the temper making the edge too soft for most tools. The steel hasn't beed damaged but you either need to grind past the blue colour ( without burning the edge again ) to reach new steel that is the correct temper or redo the entire hardening and tempering process to renew the edge.
@@df-intheshop330 👍
Some guys do not quench the temper , any explanations ?
You need to quench tools when you are drawing the temper with a heat source like a torch because one end of the tool is being overheated to force the temper colors to travel to the other end of the tool. Quenching freezes the temper colors where you want them as well as cools any remaining heat that is built up in the tool. If you didn't cool the entire tool the heat built up in the handle end of the tool would continue to travel down and ruin the temper. You don't need to worry about this if you are using an oven or furnace that is set for the exact temp you need because there is no chance of overheating the tool.
@@df-intheshop330 👍
What kind of oil did you use in the beginning?
The bucket in the video was full of used hydraulic oil. Over the years I've topped it up a few time with used motor oil. So now I would guess it's 50/50? I haven't noticed any difference in performance.
Can a temper a blade using charcoal
Any heat source will work. Before torches they would heat up a big block of steel in the fire and set the tool near that to draw the temper.
👌🏻👌🏻
What oil do you use
In this video I am using recycled motor oil but I have switched to canola oil.
flam or fire when change to in black colour i meen what is the tempreture requird fire or heat for black colour
If you mean the black fire scale - you need to heat the steel until it reaches at least a bright red colour. At that temperature or above the steel will react with the air to form the scale. Once you have cleaned off the surface to draw the temper for a tool you cannot reheat the steel to that high temperature and replace the scale without ruining the temper.
This is the answeer I was looking for!! Thank you!!!!
Maybe many people ned this information.
What kind of oil did you use? Can you use water? how long does this take?
The oil i use is mostly used motor oil. Oil hardening steels are designed to be hardened in oil. They need a slower reaction time so if you use water the amount of stress developed in the quench will cause a lot of warping and cracking.
Thanks so much, this was really helpful!
Are these steps correct?
1) check critical temperature - when it stops being magnetic
2) heat to critical temperature, quench in oil
3) if not glassy hard, retry and quench in water. if not glassy hard, stop trying
4) heat it to critical temp and let it cool off naturally - it's now soft
5) grind it or heat it until red, shape it by hammering - stop hammering when it gets to critical temperature, repeat
6) heat it to whatever oxidation color is needed for that type of tool, quench it in oil.
So, the tempering is done after the hardening in order to release post tension in the steel? But as long as the edge doesn't get blued, it will keep its hardness?
The annealing process (before hardening ) is designed to reduce the stress in the metal to prevent cracking or warping. Tempering removes some of the brittleness from the hardening process. Most tools need a little bit of flex to hold up well. The temper colors are used to show how much the steel is being heated. At a blue temper color you will have removed to much of the hardness for most types of cutting tools. Tempering balances the amount of hardness you need with the amount of shock resistance or flex you need. Files for example are not tempered because they need to be glass hard while springs are tempered to a full blue because they need to be very flexible.
Files should not be left at a full hard condition. Glass hard also means the metal will shatter just as if it was made of glass, not something you want in any cutting tool including files. Several years ago I tested some small spring steel after the quench. It shattered and flew everywhere.
@@dougmacqueen1679 so how files are treated after the quench?
@@dougmacqueen1679 so how files are treated after the quench?
@@khayyam741 Just we are clear, failure to do any tempering on a steel cutting tool will make it extremely hard and therefore very efficient at cutting. As long as it doesn't chip or break. A file is just a lot of little chisel teeth formed on a steel blank. And you really want it to survive being used. So a slight amount of temper will bring it off that glass hard state.
Hi, are there more different techniques of tempering or what, I thought that you temper it by heating it to desired temp. as described but than letting it cool slowly on room temperature?? I m confused
Matko Lendler just put it in the oven at 400 degrees Fahrenheit for an hour or two
but i m confused because I see some guys temper it by leaving it cool at room temp. and some heat it to tempering temp. and then quench it ( for the second time )
Sometimes you need to quench the part of the piece you are tempering with a torch to stop the temper colors from advancing if you have an excess amount of heat built up in the tool. Quenching doesn't affect the quality of the tempering - it's just a way of regulating the temperature. Just make sure that you don't quench any part of the tool that might be at a red heat because it will become brittle. Tempering in an oven does work great and it's the best way to make sure that you get the exact temper you want. Start at 400 & raise the heat slightly every 1/2 hour or so until you get the colors you need. The first time you do it take note of all the colors you get at the different temps so you can start closer to that mark next time.
If you are talking about taking it to the critical temp and then letting it cool slowly that is a totally different part of the process. It is confusing because some people also call that tempering but it is really called normalizing. That process is to reduce the stress in the metal before hardening. That stress will cause knife blades to warp or crack. After forging or shaping you normalize, then you harden and then you temper. When you hear people say their blades are triple tempered they are actually normalizing the blade 3 times to ensure all stress is removed before hardening.
Thanks for the answer, I dont think on normalizing, I know that s a different process with a different purpose like you said, but I thought tempering is done after hardening by heating the metal piece to wanted temperature ( light straw to blue depending what properties you need ) and than just let it cool slowly in owen, room temp. ....., did t think you can temper it just by getting to wanted tempering temperature an cooling it quickly by quenching.
Wikipedia also says this ( but found and heard that in more places than wiki :) ): "Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air."
Or there are simply two possible options for tempering: 1. get to tempering temperature and just let cool
2. get to tempering temperature and quench????
I have some chisels to treat. Thanks
so... best cllor for best result tempered steel is dark blue, am i right ???
It depends on what it will be used for. There is no single temper colour that will work for everything.
@@df-intheshop330 heat treat & tempered valve motorcycle. Tell me please... Thankss...
Question. ... can stainless steel be used as "tool steel"?
The stainless knife makers use ( or once did ) is 440c. I've never worked with it so I can't comment on how it forges but I do remember in the 80's that it was a pretty big deal that some guys were able to forge stainless so I imagine it has it's problems. Better check with the bladesmiths before you put too much time into something.
There are so many varieties of stainless, some suitable for knives, some not. 440C, which is common for knives (and pretty much all stainless in general) is very difficult to forge. Most knife makers who do stainless typically make them in what is known as the "stock removal" method. In other words, they buy their stainless in pre-cut lengths, widths and thicknesses, then use their grinders to shape the blade, bevels, etc, then send it out to a commercial heat treater. Stainless requires precise and complex heat treating in multiple cycles. You do not harden and temper stainless by heating it and quenching it in the same manner as carbon steels. It requires lengthy periods of time at precise temperatures and also precise cooling rates and multiple heating and cooling cycles.
Stainless has a very small heat range where it can be forged with a hammer. Too low and it just won't move, go slightly over the ideal range and it will crumble like cottage cheese. Even at the ideal temperature, it takes twice as much, if not more, force to forge it. If you try to work at a temp lower than ideal then you hazard shattering or cracking it. Many knife makers never try to forge it at all and just use the stock removal method of they want to make a stainless knife.
Very informative thank you!
How hot does steel need to be before you can bend it ?
This temper works for Stones?
AAAAAAAAAAAAAAAmazing
is that basic raw steel at the beginning?
This chisel is made from a coil spring
So the process you used wouldn't work near as good on raw steel I presume. @@df-intheshop330
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